1. Field of the Invention
The present invention relates to an image forming apparatus capable of preventing an image defect from occurring due to a separating discharge phenomenon caused by the rubbing between a recording material and a conveyance guide in unfixed toner that has been transferred onto the recording material by a transfer unit.
2. Description of the Related Art
In an image forming apparatus employing an electrophotographic process, such as a copying machine, a printer, and a fax machine, a developing device develops, with toner, an electrostatic latent image obtained by irradiating a uniformly-charged photosensitive member with light based on image information. A toner image is transferred onto a sheet, and then subjected to heating and fixing. Thus, an image is formed.
A guide member, such as a guide, for guiding the sheet from a transfer roller to a fixing device is used. The guide member is brought into contact with the sheet. Therefore, triboelectric charging occurs due to the rubbing between the sheet and the guide member, and a separating discharge phenomenon occurs at a trailing edge portion of the sheet when the sheet is separated from the guide member. Thus, an unfixed toner image on the sheet is disturbed, which causes an image defect in a dotted pattern or the like.
In order to prevent the separating discharge phenomenon, for example, as disclosed in Japanese Patent Application Laid-Open No. H05-333704, an electrode plate may be provided near the member that causes the separating discharge phenomenon to weaken the electric field.
However, in Japanese Patent Application Laid-Open No. H05-333704, when the electrode plate for preventing separating discharge is arranged near a high voltage application member, an application bias voltage of the high voltage application member flows to the electrode plate via the sheet. Therefore, a secondary damage such as insufficient output of the high voltage application member may be caused.